There has been an unfilled need for a large, portable motion picture screen assembly which can be quickly erected and quickly taken down, especially for outdoor viewing by large groups of people, such as college students. Such a motion picture screen assembly has to be able to withstand wind forces which create toppling problems. The motion picture screen assembly also must be simple to assemble and simple to erect and take down by relatively unskilled people. Finally, the viewing screen must be large, flat and steady in order to provide a pleasing viewing surface, and the motion picture screen assembly must be able to packed up and transported to another location in a relatively small truck.